1. Field of the Invention
This invention relates to an image recording device, more particularly to an image recording device which records color images while moving reciprocally a plural number of recording heads for inks with different colors in the direction orthogonal to the paper conveying direction.
2. Description of the Prior Art
As a color recording device using a multi-head for inks with different colors, there may be mentioned an ink-jet printer which performs color printing according to subtractive color mixing by jetting inks through jetting nozzles to have inks adhered on the same spot on a recording paper.
Color recording by ink-jet of the prior art performs image recording according to subtractive color mixing with the use of the three colors of yellow, magenta and cyan (hereinafter abbreviated as Y, M and C, respectively) or the four colors including black (hereinafter abbreviated as B) in addition to the above three colors as shown in FIG. 1. Since plural colors cannot use commonly the same nozzle, there has been known in the art a serial print system in which four recording heads 1 for exclusive use for respective colors are arranged on a carriage 2 and recording of images is performed while moving reciprocally the carriage 2 in the direction orthogonal to the conveying direction of the recording paper 3 by means of a platen 4 (as shown by the arrows in the drawing). In most of the devices performing recording according to such a system, for the purpose of accelerating the recording speed, recording is carried out in both going and returning travels of heads.
Such an image recording device which performs recording in both going and returning travels had the following drawbacks. That is, in the device as described above, recording is carried out with the recording heads 1 having orifices (jetting holes) in a vertical array being laterally arranged, whereby the order of ink jetting during recording in the going travel differs from that in the returning travel as shown in FIG. 2 (in the Figure, there is shown an example of recording heads having four orifices, and ink is jetted in the order of Y, M, C and B in the going travel, while in the order of B, C, M and Y in the returning travel). As the result, color formations were inevitably different, although the extent of difference may vary depending on the compatibility between the paper and the ink, to alter disadvantageously the finished color textures.
That is, when reciprocal recording is performed by use of recording heads having a recording width of l as shown in FIG. 1, the color recording obtained will be one as shown in FIG. 2 wherein color texture differs alternately for each interval of l.
This is because subtractive color mixing is effected on a recording paper in conventional ink jet printers and color formation by subtractive color mixing will differ depending on the order of color mixing on a recording paper which is different in the going travel from that in the returning travel. If this drawback is to be overcome by performing dot recording only by travelling in one direction, the actuation in the returning travel of the heads will be a mere displacement from the beginning to the end, whereby lowering of total recording speed will be brought about.